| 摘要 |
PURPOSE:To eliminate securely the possibility that read data is error data during reading operation by checking whether write data is recorded correctly or not as to the tolerance of error correction. CONSTITUTION:When data is written, the written data is read out to make error corrections and decide on its error state. A decision on the state after the error corrections is made by using four state signals, i.e. a code sequence number EPTR having a pointer P1 set during C1 decoding, a code sequence number ECW1 having a one-symbol error corrected during C2 decoding, a code sequence number ECW2 having a two-symbol error corrected during the C2 decoding, and a code sequence number ECER in which error correction is impossible during the C2 decoding. A judgement based upon the error state is made by a system controller 13 and a host processor 15 judges whether the data needs to be written again or not and sends a command for writing to an alternate sector when so. |
